Details
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Bug
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Status: Closed
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Critical
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Resolution: Fixed
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6.5.0, 6.0.0, 5.5.0, 5.5.1, 5.5.2, 5.5.3, 6.0.1, 6.0.2, 5.5.4, 6.0.3, 5.5.5, 5.5.6, 6.0.4, 6.5.1, 7.0.0
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1
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KV-Engine Sprint 2021 July
Description
Problem
Currently the "dcp" and "dcpagg" stats are collated by the front-end thread. This can be an expensive operation, and hence the STAT command can take a significant time to return. This means the STAT operation is tying-up a front-and thread which means that operations that happen to be allocated to the same thread get delayed for an unacceptable length of time.
Solutions
- Move the expensive part(s) of these stat groups to a background task, allowing the client operation to EWOULDBLOCK and yield execution back to the front-end thread.
- Investigate what part(s) of these stat groups ns_server needs. If the stat(s) needed are cheap then consider new stat groups which only contain the specific elements ns_server needs.
Note we might want both of these; given that dcp and dcpagg are recorded by cbcollect_info and we wouldn't want to remove them there.
Attachments
Issue Links
- blocks
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- Closed
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- Closed
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- causes
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- Closed
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- is triggering
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DOC-8403 Release note timeouts may occur during cbcollect_info
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- In Review
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Activity
| Field | Original Value | New Value |
|---|---|---|
| Link | This issue relates to CBSE-8260 [ CBSE-8260 ] |
| Fix Version/s | Cheshire-Cat [ 15915 ] |
| Issue Type | Improvement [ 4 ] | Bug [ 1 ] |
| Description | Currently the "dcp" and "dcpagg" stats are collated by the front-end thread. This can be an expensive operation, and hence the STAT command can take a significant time to return. This means the STAT operation is tying-up a front-and thread which means that operations that happen to be allocated to the same thread get delayed for an unacceptable length of time. |
| Description | Currently the "dcp" and "dcpagg" stats are collated by the front-end thread. This can be an expensive operation, and hence the STAT command can take a significant time to return. This means the STAT operation is tying-up a front-and thread which means that operations that happen to be allocated to the same thread get delayed for an unacceptable length of time. |
+Problem+
Currently the "dcp" and "dcpagg" stats are collated by the front-end thread. This can be an expensive operation, and hence the STAT command can take a significant time to return. This means the STAT operation is tying-up a front-and thread which means that operations that happen to be allocated to the same thread get delayed for an unacceptable length of time. +Solutions+ # Move the expensive part(s) of these stat groups to a background task, allowing the client operation to EWOULDBLOCK and yield execution back to the front-end thread. # Investigate what part(s) of these stat groups ns_server needs. If the stat(s) needed are cheap then consider new stat groups which only contain the specific elements ns_server needs. Note we might want both of these; given that {{dcp}} and {{dcpagg}} are recorded by {{cbcollect_info}} and we wouldn't want to remove them there. |
| Summary | Move STAT "dcp" and "dcpagg" to background threads | Reduce impact of STAT "dcp" and "dcpagg" on other front-end operations |
| Fix Version/s | backlog [ 15925 ] | |
| Fix Version/s | Cheshire-Cat [ 15915 ] |
| Issue Type | Bug [ 1 ] | Improvement [ 4 ] |
| Fix Version/s | CheshireCat.Next [ 16908 ] | |
| Fix Version/s | backlog [ 15925 ] |
| Priority | Major [ 3 ] | Critical [ 2 ] |
| Fix Version/s | 7.0.1 [ 17104 ] | |
| Fix Version/s | CheshireCat.Next [ 16908 ] |
| Labels | releasenote |
| Rank | Ranked higher |
| Sprint | KV-Engine Sprint 2021 July [ 1660 ] |
| Rank | Ranked lower |
| Assignee | Daniel Owen [ owend ] |
| Issue Type | Improvement [ 4 ] | Bug [ 1 ] |
| Summary | Reduce impact of STAT "dcp" and "dcpagg" on other front-end operations | STAT "dcp" and "dcpagg" adversely affect front-end operation latency |
| Rank | Ranked higher |
| Rank | Ranked higher |
| Assignee | James Harrison [ james.harrison ] |
| Status | Open [ 1 ] | In Progress [ 3 ] |
| VERIFICATION STEPS | Stat correctness guarded by existing unit tests | |
| Resolution | Fixed [ 1 ] | |
| Status | In Progress [ 3 ] | Resolved [ 5 ] |
| Assignee | James Harrison [ james.harrison ] | Daniel Owen [ owend ] |
| Affects Version/s | 7.0.0 [ 17233 ] |
| Assignee | Daniel Owen [ owend ] | Ashwin Govindarajulu [ ashwin.govindarajulu ] |
| Status | Resolved [ 5 ] | Closed [ 6 ] |
| Fix Version/s | 7.0.2 [ 18012 ] |
| Fix Version/s | 7.0.1 [ 17104 ] |